table {
  margin: auto;
  border-collapse: collapse;

}

tr {
  width: 50px;
  height: 50px;
}

td {
  border: 1px solid #888888;
  width: 50px;
  height: 50px;
  background-color: #EEEEEE;
  text-align: center;
  font-size: 2em;
}